Casing expanding mandrel

ABSTRACT

A mandrel for swaging and thereby expanding a collapsed oil well or similar casing to restore the same to its original size and form, the mandrel having a mandrel body formed to have successively smaller cylindrical portions in which are provided groups of conduit-swaging balls in circular arrangement around the axis of said body, the groups of balls, starting at the lower end of the mandrel body, being arranged in successively larger circles so the casing expansion size increases as the mandrel, on the end of a drilling string, is being rotated and lowered as permitted by the progressive expansion of the casing.

United States Patent [191 Bateman June 25, 1974 CASING EXPANDING MANDREL [76] Inventor: J. W. Bateman, 9245 Priscilla Ave.,

Downey, Calif. 90242 22 Filed: May 23, 1973 [Zl] Appl. No.: 363,245

[56] c References Cited UNITED STATES PATENTS 12/1907 Jones .l.72/75 12/1911 ll/l925 l/l926 8/1926 I ,56 l ,4 l 8 1,569,729 1,597.2 l 2 7 Primary Examiner-Lowell A. Larson 5 7] ABSTRACT A mandrel for swaging and thereby expanding a collapsed oil well or similar casing to restore the same to its original size and form, the mandrel having a mandrel body formed to have successively smaller cylindrical portions in which are provided groups of conduit-swaging balls in circular arrangement around the axis of said body, the groups of balls, starting at the lower end of the mandrel body, being arranged in successively larger circles so the casing expansion size increases as the mandrel, on the end of a drilling string, is being rotated and lowered as permitted by the progressive expansion of the casing.

5 Claims, 2 Drawing Figures,

CASING EXPANDING MANDREL BACKGROUND OF THE INVENTION 1. Field of the Invention:

Restoring well casing which had collaped bent and/or otherwise been deformed to enable efficient continued operation of a drilling string, as well as restoring a de formed casing to a smooth tubular form that offers minimum resistance to upward flow of a producing well.

2. Description of the Prior Art: 1

A professional investigation of the prior art turned up the following US. Pat. Nos; 1,010,954 1,594,114 2,183,921 3,201,827 3,339,388.

Of the above patents, all but Pat. No. 3,339,388 retain their swaging balls in grooves or seats by lips or other such overstanding peripheral portions of a mandrel so that more than half the mass 'of each ball is retained in the grooves or seats. Pat. No. 1,010,954 has such retaining lips and also provides a special means for removing the balls in successive grooves from the grooves in which they are confined.

The present stepped mandrel body, the seats in said body to receive one-half the mass of each swaging ball,

, and the rings or collars with raceways for retaining the balls in swaging position in their seats, are features of the present invention that have no teaching in the above listed prior art.

SUMMARY OF THE INVENTION A mandrel body adapted to be attached to the lower end of a drill string, the same, from its upper end towardits lower end, having successively reduced cylindrical portions in stepped form, theouter faces of said cylindrical portions having hemispherical cavities or seats in circular arrangement for hardened balls that have a rolling fitinsaid cavities. The mandrel body is fitted with ball-retaining rings that are provided on the opposite ends thereof with raceways with which said balls are engaged, the outer diametral sizes of the ballretaining rings or collars being smaller than a circle circumscribed around each respective circular arrangement of balls. The balls of each said arrangement having the portions thereof that protrude beyond the mentionedcavities and are adjacent thereto, engaged in the raceways of the ball-retaining ringson upper and lower portions of each circular arrangement of balls.

At the upper and lower ends of the mandrel body are provided similar retaining rings with the exception that the upper ring has one raceway in its lower portion, and

the lower ring has one raceway in its upper portion, the

latter ring being provided with a nose extension that guides the mandrel into and through a casing to be expanded.

An object of this invention is to provide a casingswaging mandrel, as above characterized, in which the sets of swaging balls are effectively retained in swaging condition in their cavities or seats.

Another object of the invention is to provide for a fixed location of the means that retain the ballretaining means so the balls have free rotation, as caused by friction engagement with a casing wall.

This invention also has for its objects to provide such means that are positive in operation, convenient in use, easily installed in a working position and easily disconnected therefrom, economicalof manufacture, relatively simple, and of general superiority and serviceability.

The invention also comprises novel details of con struction and novel combinations and arrangements of parts, which will more fully appear in the course of the following description, which is based on the accompanying drawing. However, said drawing merely shows, and the following specification merely describes, one embodiment of the present invention, which is given by way of illustration or example only.

In the drawing, like reference characters designate similar parts of the several views.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a foreshortened elevational view, with portions thereof in longitudinal section, of a casing expanding mandrel according to the present invention.

FIG. 2 is an enlarged elevational view, partly in vertical section, of the upper portion of the tool shown in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT The present swagingand expanding tool comprises, generally, a mandrel body 5, a plurality of circularly arranged swaging balls 6 mounted on the outer face of said body, a plurality of rings or collars 7 on said body, one between each two circular arrangements of balls 6, a top ring 8 on said body engaged with the uppermost circular arrangement of balls, and a nose 9 connected to the lower end of the mandrel body and incorporating a retainer ring 10 and serves to lock together the assembly of the balls 6 and retainer rings 7, 8 and 10.

The mandrel body 5 is shown as an elongated member that is advantageously made of steel or other hard and wearresisting metal. The same is shown with an upper end 15 having a threaded box 16 for the pin on the end of a drilling string, with an enlargement l7 having a downwardly facing shoulder 18, and with a lower extension of successivelly smaller diameter cylindrical portions 19, 19a, 19b and 190, it being understood that the portion broken out between cylindrical portions 19a and 19b may have one or more intermediate successively smaller diameter cylindrical portions smaller than portion 19a and larger than portion 19b. It will be noted that each of said cylindrical portions terminates at its lower end in a downwardly facing annular shoulder 20.

Each of said cylindrical portions 19-19c is provided with at least one circular arrangement of preferably uniform cavities or seats 21 that are, at their maximum depth, hemispherical and each said seat being fitted with a ball 6 of polished steel or similarly hardened metal. The number of seats or of balls may vary provided at least three of the latter are used.

While two adjacent circular arrangements of cavities may be of the same hemispherical size and depth, of any two adjacent arrangements, the size and depth of the seats 21 in the smaller diameter cylindrical portion are smaller than the size and depth of the seats in the larger portion. The balls 6 in said smaller seats are also smaller, accordingly. Thus, the circumscribing circles around the successively smaller arrangements of balls are progressively smaller toward the lower end of the mandrel.

The balls 6 are retained in their seats 21 by a set of rings or collars 22 which, in' addition to the top ring 8, engage the respective balls 6 at their upper and lower sides, each said ring 22 in its upper and lower edges,

being provided with a raceway 23, and the top ring 8 with a similar raceway in its lower edge. lt will be seen that said raceways have outer lips that engage over the protruding portions of the balls and serve to retain them in their seats.

It will be noted that, to achieve the desired engagement of the balls 6 by the raceways 23 so as to have a non-binding engagement between the balls and the rings, the latter are provided with upwardly directed shoulders 24 that are so located between upper and lower edges of the respective rings that the raceways have the desired rolling engagement with the balls 6 when said shoulders 24 are engaged with the shoulders 20 of the mandrel body 5.

The lower end of the mandrel is tightened up by the nose 9, as in FIG. 7, the screws 25 of each ring being tightly set to lock the assembly.

It will be understood that the raceways may be formed on transverse curvatures that assure rolling clearance with the balls and allows for the balls to be inserted into their respective seats with the raceway thereabove. Thus suitable rolling clearance movement of the ball may be achieved,

The elements of the mandrel are assembled on the body from the bottom up in successive stages. After the top ring 8 is placed on the cylindrical portion 19 and against the shoulder 18, the first arrangement of balls 6 are dropped in their seats 21, the rolling clearance of the balls in their seats providing assemblage clearance for said balls to engage in the raceway 23 of said ring 8. Now the topmost ring 7 is fitted onto said cylindrical portion 19.

If a second arrangement of balls 6 is to be provided on the uppermost cylindrical portion 19 of the mandrel body, a second ring 7 one without a shoulder 24 may be positioned on the cylindrical portion 19. Thereafter, until the nose 9 is to be affixed to the tool, arrangements of balls 6 and rings or collars 7 are alternately fitted to the mandrel body 5. When the screws 25 are in place, the mandrel is completely assembled and is ready for insertion into a collapsed or otherwise distorted casing C. When the string on which the mandrel is attached is rotated and lowered, the successive arrangements of balls 6 expand and straighten said casing by swaging action by engagement with the inner face of said casing.

While the foregoing has illustrated and described what is now contemplated to be the best mode of carrying out the invention, the construction is, of course, subject to modification without departing from the spirit and scope of the invention.

Having thus described the invention, what is claimed and desired to be secured by Letters Patent is:

1. A casing expanding mandrel comprising:

an elongated mandrel body having an upper end for attachment to a drill string, said mandrel body having successively cylindrically smaller portions from said upper end downwardly, each said cylindrically smaller portion having a downwardly facing shoulder;

at least one set of circularly arranged seats that are, at most, of hemispherical depth in the cylindrical surface of each said body portion;

a set of swaging balls in each said set of seats, each ball protruding from its seat for at least half its spherical mass, and

a set of rings, one between each two adjacent sets of swaging balls, having upper and lower edge raceways engaged with said balls to retain the latter in their seats,

said rings having inner upwardly facing shoulders that have position-limiting engagement with the mentioned downwardly facing shoulders of the mandrel body.

2. A casing expanding mandrel according to claim 1 in which each of the mentioned raceways has peripheral lips that have the mentioned retaining engagement with the swaging balls.

3. A casing expanding mandrel according to claim 2 in which fastener means are provided to connect the rings to the mandrel body to retain the mentioned shoulder-to-shoulder engagement of the rings and the mandrel body.

4. A casing expanding mandrel according to claim 1 in which, at the lowermost end of the mandrel, is provided a nose member that is adapted for lead-in engagement of the mandrel with the casing.

5. A casing expanding mandrel according to claim 4 in which said nose member is formed as an integral part of the lowermost ring. 

1. A casing expanding mandrel comprising: an elongated mandrel body having an upper end for attachment to a drill string, said mandrel body having successively cylindrically smaller portions from said upper end downwardly, each said cylindrically smaller portion having a downwardly facing shoulder; at least one set of circularly arranged seats that are, at most, of hemispherical depth in the cylindrical surface of each said body portion; a set of swaging balls in each said set of seats, each ball protruding from its seat for at least half its spherical mass, and a set of rings, one between each two adjacent sets of swaging balls, having upper and lower edge raceways engaged with said balls to retain the latter in their seats, said rings having inner upwardly facing shoulders that have position-limiting engagement with the mentioned downwardly facing shoulders of the mandrel body.
 2. A casing expanding mandrel according to claim 1 in which each of the mentioned raceways has peripheral lips that have the mentioned retaining engagement with the swaging balls.
 3. A casing expanding mandrel according to claim 2 in which fastener means are provided to connect the rings to the mandrel body to retain the mentioned shoulder-to-shoulder engagement of the rings and the mandrel body.
 4. A casing expanding mandrel according to claim 1 in which, at the lowermost end of the mandrel, is provided a nose member that is adapted for lead-in engagement of the mandrel with the casing.
 5. A casing expanding mandrel according to claim 4 in which said nose member is formed as an integral part of the lowermost ring. 